This invention pertains to a cellulosic fiberboard panel, which is reinforced in a novel manner, and to a novel method to reinforce a cellulosic fiberboard panel. This invention contemplates that reinforcing bands, which may be cementitious, are applied on an expansive surface of a cellulosic fiberboard panel.
Commonly, cellulosic fiberboard panels are made by severing each panel, via water jets or otherwise, from a continuous web of cellulosic fiberboard, as made on a fiberboard-making machine, such as a Fourdrinier machine, from cellulosic fibers, which may be wood fibers, bagasse fibers, or other cellulosic fibers. Cellulosic fiberboard panels are used widely in building construction, as wall sheathing, as insulating panels, as roofing underlayments, as flooring underlayments, and otherwise.
Characteristically, unless made, coated, or treated with cementitious materials, asphaltic materials, or other non-permeable materials, cellulosic fiberboard panels are permeable to water vapor. Because of their permeability to water vapor, cellulosic fiberboard panels are desirable for installations where mold or mildew might thrive unless water vapor that would be otherwise trapped could permeate such panels, such as installations of wall sheathing over spaced studs, at outer walls of buildings. However, as compared to plywood panels and to other building panels, cellulosic fibreboard panels are not as strong, unless reinforced.
As exemplified in numerous prior patents including U.S. Pat. Re. 32,329, which is a reissue of U.S. Pat. No. 4,339,405, and including U.S. Pat. No. 4,402,751, U.S. Pat. No. 4,406,703, U.S. Pat. No. 4,981,518, U.S. Pat. No. 5,744,078, U.S. Pat. No. 5,846,894, and U.S. Pat. No. 6,001,169, it has been known heretofore to blend cementitious materials with cellulosic fibers, whereby to make reinforced, water vapor-impermeable, cellulosic fiberboard panels.
In a panel made of cellulosic fiberboard and having two expansive surfaces, two longitudinal edges, and two transverse edges, each expansive surface having four corners and each expansive surface having an overall area, this invention provides an improvement wherein the panel has bands of a reinforcing material, for which a cementitious material is preferred. The bands cover a minor portion of the overall area of a given one of the expansive surfaces. The panel is devoid of the reinforcing material except at the bands.
The bands may include two diagonal bands, each of which extends between diagonally opposite ones of said corners of the given one of the expansive surfaces. The bands may include two longitudinal bands, each of which extends along a respective one of the longitudinal edges of the given one of the expansive surfaces. The bands may include two transverse bands, each of which extends along a respective one of the transverse edges of the given one of the expansive surfaces. Preferably, the bands include such diagonal, longitudinal, and transverse bands.
As a method to reinforce a panel made of cellulosic fiberboard and having two expansive surfaces, two longitudinal edges, and two transverse edges, each expansive surface having four corners and each expansive surface having an overall area, this invention provides a step of wherein applying bands of a reinforcing material, for which a cementitious material is preferred, so as to cover a minor portion of the overall area of a given one of the expansive surfaces, wherein the panel is devoid of the reinforcing material except at the bands.
Two diagonal bands of the reinforcing material may be thus applied so that each of the diagonal bands extends between diagonally opposite ones of said corners of the given one of the expansive surfaces. Two longitudinal bands of the reinforcing material may be thus applied so that each of the longitudinal bands extends along a respective one of the longitudinal edges of the given one of the expansive surfaces. Two transverse bands of the reinforcing material may be thus applied so that each of the transverse bands extends along a respective one of the transverse edges of the given one of the expansive surfaces. Preferably, such diagonal, longitudinal, and transverse bands are applied so as to extend as noted.